[PATCH v2] omapfb: dss: Handle return error in dss_init_ports.

[PATCH v2] omapfb: dss: Handle return error in dss_init_ports.

[Arvind Yadav]

Here, dss_init_ports is not handling return error form
dpi_init_port and sdi_init_port. Now dss_init_ports is returning
always 0. And it's making below code as a dead code.

static int dss_bind(struct device *dev)
{
  .
  .
  r = dss_init_ports(pdev); //dss_init_ports will return always 0
  if (r)// This condition will always false
      goto err_init_ports; //Dead Code
  .
  .
}

This change is to handle return error from dpi_init_port and
sdi_init_port. Also, It will remove dead code from function 'dss_bind'.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
---
 drivers/video/fbdev/omap2/omapfb/dss/dss.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/video/fbdev/omap2/omapfb/dss/dss.c b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
index 47d7f69..87eb10c 100644
--- a/drivers/video/fbdev/omap2/omapfb/dss/dss.c
+++ b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
@@ -946,6 +946,7 @@ static int dss_init_ports(struct platform_device *pdev)
 	struct device_node *parent = pdev->dev.of_node;
 	struct device_node *port;
 	int r;
+	int ret = 0;
 
 	if (parent = NULL)
 		return 0;
@@ -972,17 +973,20 @@ static int dss_init_ports(struct platform_device *pdev)
 
 		switch (port_type) {
 		case OMAP_DISPLAY_TYPE_DPI:
-			dpi_init_port(pdev, port);
+			ret = dpi_init_port(pdev, port);
 			break;
 		case OMAP_DISPLAY_TYPE_SDI:
-			sdi_init_port(pdev, port);
+			ret = sdi_init_port(pdev, port);
 			break;
 		default:
 			break;
 		}
 	} while ((port = omapdss_of_get_next_port(parent, port)) != NULL);
 
-	return 0;
+	if (ret)
+		dss_uninit_ports(pdev);
+
+	return ret;
 }
 
 static void dss_uninit_ports(struct platform_device *pdev)
-- 
1.9.1

Re: [PATCH v2] omapfb: dss: Handle return error in dss_init_ports.

[Bartlomiej Zolnierkiewicz]

Hi,

On Thursday, February 09, 2017 03:28:01 PM Arvind Yadav wrote:
> Here, dss_init_ports is not handling return error form
> dpi_init_port and sdi_init_port. Now dss_init_ports is returning
> always 0. And it's making below code as a dead code.
> 
> static int dss_bind(struct device *dev)
> {
>   .
>   .
>   r = dss_init_ports(pdev); //dss_init_ports will return always 0
>   if (r)// This condition will always false
>       goto err_init_ports; //Dead Code
>   .
>   .
> }
> 
> This change is to handle return error from dpi_init_port and
> sdi_init_port. Also, It will remove dead code from function 'dss_bind'.
> 
> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
> ---

Please include version history here when submitting new
versions.

>  drivers/video/fbdev/omap2/omapfb/dss/dss.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/video/fbdev/omap2/omapfb/dss/dss.c b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> index 47d7f69..87eb10c 100644
> --- a/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> +++ b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> @@ -946,6 +946,7 @@ static int dss_init_ports(struct platform_device *pdev)
>  	struct device_node *parent = pdev->dev.of_node;
>  	struct device_node *port;
>  	int r;
> +	int ret = 0;
>  
>  	if (parent = NULL)
>  		return 0;
> @@ -972,17 +973,20 @@ static int dss_init_ports(struct platform_device *pdev)
>  
>  		switch (port_type) {
>  		case OMAP_DISPLAY_TYPE_DPI:
> -			dpi_init_port(pdev, port);
> +			ret = dpi_init_port(pdev, port);
>  			break;
>  		case OMAP_DISPLAY_TYPE_SDI:
> -			sdi_init_port(pdev, port);
> +			ret = sdi_init_port(pdev, port);
>  			break;
>  		default:
>  			break;
>  		}
>  	} while ((port = omapdss_of_get_next_port(parent, port)) != NULL);

What about the other issue raised by me?

Shouldn't initialization be stopped after first failure?

i.e.:

        } while (!ret && (port = omapdss_of_get_next_port(parent, port)) != NULL);

Otherwise it is possible to return a success in case when
- initialization of the first port fails
- initialization of the second port is successful
 
> -	return 0;
> +	if (ret)
> +		dss_uninit_ports(pdev);
> +
> +	return ret;
>  }
>  
>  static void dss_uninit_ports(struct platform_device *pdev)

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH v2] omapfb: dss: Handle return error in dss_init_ports.

[kbuild test robot]

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Hi Arvind,

[auto build test ERROR on linus/master]
[also build test ERROR on v4.10-rc7 next-20170209]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Arvind-Yadav/omapfb-dss-Handle-return-error-in-dss_init_ports/20170209-201712
config: arm-omap2plus_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=arm 

All error/warnings (new ones prefixed by >>):

   drivers/video/fbdev/omap2/omapfb/dss/dss.c: In function 'dss_init_ports':
>> drivers/video/fbdev/omap2/omapfb/dss/dss.c:987:3: error: implicit declaration of function 'dss_uninit_ports' [-Werror=implicit-function-declaration]
      dss_uninit_ports(pdev);
      ^~~~~~~~~~~~~~~~
   drivers/video/fbdev/omap2/omapfb/dss/dss.c: At top level:
>> drivers/video/fbdev/omap2/omapfb/dss/dss.c:992:13: warning: conflicting types for 'dss_uninit_ports'
    static void dss_uninit_ports(struct platform_device *pdev)
                ^~~~~~~~~~~~~~~~
>> drivers/video/fbdev/omap2/omapfb/dss/dss.c:992:13: error: static declaration of 'dss_uninit_ports' follows non-static declaration
   drivers/video/fbdev/omap2/omapfb/dss/dss.c:987:3: note: previous implicit declaration of 'dss_uninit_ports' was here
      dss_uninit_ports(pdev);
      ^~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

vim +/dss_uninit_ports +987 drivers/video/fbdev/omap2/omapfb/dss/dss.c

   981			default:
   982				break;
   983			}
   984		} while ((port = omapdss_of_get_next_port(parent, port)) != NULL);
   985	
   986		if (ret)
 > 987			dss_uninit_ports(pdev);
   988	
   989		return ret;
   990	}
   991	
 > 992	static void dss_uninit_ports(struct platform_device *pdev)
   993	{
   994		struct device_node *parent = pdev->dev.of_node;
   995		struct device_node *port;

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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